§ 78. Effect of assignment. The assignment vests in the trustee or trustees all the petitioner's interest, legal or equitable, at the time of its execution, in any real or personal property, not exempt by law from levy and sale by virtue of an execution; and any contingent interest which may vest within three years thereafter. When a contingent interest so vests, it passes to the trustee, in the same manner as it would have vested in the petitioner, if he had not made an assignment.